非典型病原体所致社区获得性肺炎的临床研究

目的探讨社区获得性肺炎（community-acquired pneumonia，CAP）各种病原体的构成及非典型病原体所致CAP的临床特点，以提高诊断与治疗水平。方法收集2004年2月至2006年12月在本院诊治的成人CAP病例，采用间接免疫荧光法（检测肺炎支原体IgM抗体、肺炎衣原体IgM抗体及军团菌IgG抗体）和痰液细菌分离培养检测患者的病原体。分析CAP病原体的构成。选取31例（占27．4％）由非典型病原体（肺炎支原体、肺炎衣原体）所致CAP患者为观察组，46例（占40．7％）细菌性肺炎患者为对照组，分别对两组患者的临床表现、辅助检查、治疗及转归情况进行回顾性分析。结果肺炎支原体24例（21．2％）是最常见的病原体，其后依次为肺炎链球菌14例（12．4％）、流感嗜血杆菌9例（8．0％）、肺炎衣原体7例（6．2％）、大肠埃希菌2例（1．8％）、军团菌1例（0．8％）、卡他莫拉菌1例（0．8％）。有6例患者（5．3％）为非典型病原体与细菌混合感染。观察组的临床症状以干咳（P〈0．05）、咳白黏痰（P〈0．01）、胸闷、气促（P〈0．01）多见；观察组中外周血白细胞计数正常及中性粒细胞比例正常的患者较多（P〈0．01，P〈0．05）；观察组的胸部X线片表现以斑点状或斑片状阴影为主（P〈0．05），双肺纹理增粗明显（P〈0．05），多叶浸润比例高（P〈0．05）。结论非典型病原体（肺炎支原体、肺炎衣原体、军团菌）是CAP的主要病原体。对有这类表现的CAP患者要及早检测肺炎支原体抗体、肺炎衣原体抗体、军团菌抗体以期及早明确诊断，抗生素治疗上首选大环内酯类或喹诺酮类。     

北京地区成人社区获得性肺炎非典型病原体流行病学调查

目的　对引起社区获得性肺炎 (CAP)的病原体进行流行病学调查 ,加强对非典型致病原重要性的认识。方法　收集 2 0 0 1年 11月至 2 0 0 2年 6月CAP患者共 10 3例。分别检测患者急性期及恢复期肺炎支原体、嗜肺军团菌、肺炎衣原体血清抗体。应用聚合酶链反应 (PCR)分别扩增肺炎支原体P1黏附蛋白基因及肺炎衣原体 16SrRNA基因。应用酶免疫测定 (EIA)方法检测尿中嗜肺军团菌抗原。取患者急性期痰标本进行细菌培养 ,应用常规方法分离鉴定细菌。结果　 10 3例CAP患者 ,病原体检出率为 48.5%。 2 3例 (2 2 .3 % )检出肺炎支原体 ,3例 (2 .9% )检出嗜肺军团菌 ,2例 (1.9% )检出肺炎衣原体。 12例分离出肺炎链球菌 (11.7% )、9例分离出流感嗜血杆菌 (8.7% )、7例分离出肺炎克雷伯菌 (6.8% )。 6例患者存在混合感染 (5.8% ) ,其中 5例为肺炎支原体混合其他病原体。结论　非典型病原体尤其是肺炎支原体感染在CAP中占据重要地位 ;肺炎链球菌和流感嗜血杆菌仍为常见的致病细菌 ;混合感染不容忽视     

老年社区获得性肺炎病原学分析

目的研究老年社区获得性肺炎患者的病原体分布。方法收集2005年6月-2008年5月在我院住院的128例老年CAP患者,留取呼吸道分泌物进行细菌培养,分离鉴定细菌并进行药物敏感性试验,同时检测患者急性期和恢复期肺炎支原体、肺炎衣原体、嗜肺军团菌血清抗体。结果 128例CAP患者60例（46.9%）病原学检查阳性,病原菌45株,其中主要为流感嗜血杆菌14株,肺炎克雷伯杆菌12株,肺炎链球菌10株。非典型病原阳性18例,主要为肺炎支原体13例,肺炎衣原体4例,3例为混合感染。流感嗜血杆菌对氨苄西林耐药率为14.3%;肺炎链球菌对青霉素不敏感率为30%,对阿齐霉素耐药率为60%;肺炎克雷伯菌产酶率16.7%,对含β-内酰胺酶抑制剂的复方抗生素制剂和亚胺培南敏感。结论老年患者肺炎以革兰阴性菌为优势菌株,对喹诺酮类和第3代头孢菌素具有不同程度的耐药性,对革兰阴性菌选用含有酶抑制剂的复方抗生素制剂或亚胺培南,非典型病原体的感染也占重要地位。     

广西成人社区获得性肺炎889例病原学多中心调查

目的为掌握广西地区成人社区获得性肺炎(CAP)的病原学构成情况,比较广西农村和城市CAP的病原学构成特点,推进广西地区CAP的规范化诊疗。方法收集2008-01~2010-12广西14所县市级医院的889例CAP患者,进行病原学调查,并根据地域分为城市地区(城市组331例)和农村地区(农村组578例),比较病原学构成比差异。结果研究期CAP病例中阳性422例患者入选,共检出486株病原菌,前五位的病原菌为肺炎支原体(138/486,28.40%)、流感嗜血杆菌(88/486,18.11%)、肺炎链球菌(77/486,15.84%)、肺炎克雷伯杆菌(53/486,10.91%)和肺炎衣原体(43/486,8.94%)。农村组肺炎支原体、铜绿假单胞菌感染的CAP比例高于城市组(41.12%vs 19.72%和5.58%vs 1.73%),而肺炎链球菌、嗜肺军团菌感染低于城市组(8.1%vs 21.11%和3.05%vs 7.96%)。城市组细菌(除外嗜肺军团菌)多见(183例,占63.3%),农村组则以非典型病原体多见(104例,占52.8%)。结论广西成人CAP病原学以肺炎支原体最常见,流感嗜血杆菌和肺炎链球菌也是常见菌群。广西农村地区以非典型病原菌为主,城市则以细菌常见。     

社区获得性肺炎住院患者病原体构成分析

目的了解近四年来唐山地区成人社区获得性肺炎住院患者病原谱构成。方法收集在河北联合大学附属医院呼吸内科住院治疗的400例成人社区获得性肺炎患者资料,分析其病原谱构成。1400例成人CAP住院治疗患者中,病原体阳性患者为245人,病原体检出率为61．3％。细菌培养阳性。结果细菌感染患者140人,细菌检出率为35％,其中革兰氏阳性细菌占29．9％,革兰氏阴性细菌占70．1％,最常见致病菌为肺炎克雷伯杆菌（9．8％）、肺炎链球菌（6．5％）、铜绿假单胞菌（4．5％）。血清学检测非典型病原体IgM抗体阳性患者50人,检出率为（12．5％）,病毒抗体阳性患者55人,检出率（13．8％）。结论唐山地区成人CAP患者最常见的感染类型为细菌感染、其后依次非典型性病原体感染、病毒感染,其中细菌感染以革兰氏阴性细菌为主。     

齐齐哈尔市156例小儿社区获得性肺炎的病原学特点及影响预后的相关因素分析

目的探讨齐齐哈尔市社区儿童获得性肺炎(CAP)的病原学特点及影响预后的相关因素。方法对本市2019年1月-2020年1月确诊的156例CAP患儿分别采集其呼吸道分泌物作细菌培养、鉴定及病原菌耐药性分析,采集患儿静脉血,分离血清,采用酶联免疫吸附法(ELISA)检测病毒及非典型病原体IgM抗体;收集患儿临床资料,对影响CAP预后的相关因素进行单因素及多因素Logistic回归分析。结果 156例CAP患儿共检出病原体117株(75.00%)。其中细菌30株(25.64%),以肺炎链球菌多见;病毒36株(30.77%),以呼吸道合胞病毒多见;非典型病原体51株(43.59%),其中肺炎支原体36株(30.77%)、肺炎衣原体9株(7.69%)、沙眼衣原体4株(3.42%)、嗜肺军团菌2株(1.71%)。30例患儿(25.64%)存在混合感染,以支原体和细菌/病毒感染多见。细菌感染以肺炎链球菌、肺炎克雷伯菌和大肠埃希菌多见。药敏试验测定肺炎链球菌对万古霉素敏感率为100.00%,对红霉素、青霉素、阿奇霉素、四环素的耐药率为10.00%～20.00%。肺炎克雷伯菌和大肠埃希菌对氨苄西林呈高度耐药,对头孢三代部分耐药,对哌拉西林/他唑巴坦和亚胺培南敏感率均为100.00%。多因素Logistic回归分析显示,年龄3岁、低氧血症、神志不清、合并多重感染、初始抗菌联合用药均是引起CAP患儿预后不良的独立危险因素(均P0.05)。结论儿童CAP病原体以肺炎支原体最为常见,其次为肺炎链球菌、肺炎克雷伯菌及大肠埃希菌。临床应根据患儿的病原学特点合理用药,同时还应重点关注低龄、低氧血症、合并多重感染等影响CAP患儿预后不良的危险因素,采取针对性措施,提高疗效。     

肺炎支原体感染的实验室研究进展

北京地区成人社会获得性肺炎（CAP）的致病原进行多中心抽样调查,结果显示在被调查的665例CAP中,在610例同时进行了细菌与非典型病原体检测的患者中,肺炎支原体是最常见的病原体,阳性率为20.7%（126例）,其次为肺炎链球菌10.3%（63例）。从上述初步调查结果看,     

慢性阻塞性肺疾病急性加重期患者病原体检测分析

目的了解慢性阻塞性肺疾病病情急性加重期患者（AECOPD）的病原学特点,为进一步提高其诊治水平提供思路。方法对165例AECOPD患者行痰细菌定量培养,血清支原体、衣原体、嗜肺军团菌抗体检测以及鼻咽拭子病毒RT—PCR检测,分析其特点。结果病原体检测阳性率为70．3％（116／165）。其中痰检细菌阳性率为47．3％;非典型病原体阳性率为21．2％;病毒检测阳性率为24．8％;细菌和非典型病原体均为阳性21例,阳性率为12．7％;细菌和病毒均为阳性17例,阳性率为10．3％。结论AECOPD患者病原体以细菌最为常见,以革兰阴性杆菌为主,非典型病原体多与细菌混和感染,病毒感染多见于呼吸困难的患者。非感染因素导致的AECOPD病情加重不容忽视。     

非典型病原体在获得性肺炎中的地位

目的探讨非典型病原体在非重症社区获得性肺炎中地位。方法收集宁波市鄞州区农民2006年1月至2007年7月的CAP患者共96例，分别检测就诊时及2～4周后的血清肺炎支原体、肺炎衣原体及嗜肺军团菌抗体的滴度，以出现4倍及4倍以上的增高为诊断标准。结果所有患者的初期治疗均使用β-内酰胺类抗生素，3天治疗效果不佳者，进行抗生素升级治疗同时加用大环内酯类，或单用呼吸喹诺酮类抗生素，所有患者病情都得到控制，96例患者测出非典型病原体21例，其中肺炎支原体14例，肺炎衣原体4例，嗜肺军团菌3例。但21例患者中有11例单用β-内酰胺类抗生素治疗成功，10例加用大环内酯类，或单用呼吸喹诺酮类抗生素。结论农村地区社区获得性肺炎的病原体中，非典型病原体占一定的比例，可能以混合感染为主，其初始治疗可不必覆盖非典型病原体。     

非典型病原体的实验室检测技术及其临床应用前景

非典型病原体包括肺炎支原体、肺炎衣原体、嗜肺军团菌等,在社区获得性肺炎(community-acquired pneumonias,CAP)中占有重要的地位,其病原学诊断对于临床非典型肺炎患者的治疗和预后至关重要.目前,非典型病原体的检测存在许多局限性:(1)从非典型肺炎患者获得合格的检测标本较困难;(2)常规培养检测非典型病原体的临床微生物室还不常见;(3)目前非典型病原体检测技术的敏感度和特异度不够理想.尽管如此,分子生物学等检测技术已越来越多地应用于非典型病原体的病原学诊断,这给临床诊断和治疗带来了希望.     

Community-acquired pneumonia: the clinical dilemma

Community-acquired pneumonia (CAP) is the sixth most common cause of death in the United States. Despite its frequency and mortality, specific etiologic diagnosis remains a major clinical challenge. The organisms most commonly implicated in CAP are Streptococcus pneumoniae, Mycoplasma pneumoniae, Legionella pneumophila, Haemophilus influenzae, Chlamydia pneumoniae (TWAR), and viruses. Clinical and radiographic criteria have proven to be of little value in determining the etiology of CAP. Laboratory studies, including Gram's stain and culture of sputum, have also been shown to be of severely limited value to the clinician faced with the patient with CAP. Antibiotic therapy must, therefore, generally be empiric. Regimens including erythromycin either as a single agent or coupled with an aminoglycoside or cephalosporin appear to be most efficacious.     

Diagnosis of atypical pathogens in patients hospitalized with community-acquired respiratory infection

The object of our study was to determine the proportion of atypical respiratory pathogens among patients hospitalized with a community-acquired respiratory infection. From September 1997 to May 1999, 159 patients (57% male, median age 55, range 1-88 y) admitted to 3 regional hospitals for a community acquired respiratory infection, were enrolled in the study. Microbiological diagnosis for the atypical pathogens Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila was performed with PCR on a throat swab, sputum and/or broncho alveolar lavage (BAL). In addition, Legionella species other than L. pneumophila (L. non-pneumophila species) were detected by PCR. Two serum samples were collected and processed for M. pneumoniae and C. pneumoniae serology. In total, 27 patients (17%) were diagnosed with an atypical pathogen. Infection with M. pneumoniae was detected in 19 patients (12%) (PCR positive n = 7), with C. pneumoniae in 5 patients (3%) (PCR positive n = 0) and with L. pneumophila in 4 patients (2.5%) (PCR positive n = 4). In 54 (34%) patients routine microbiological investigations revealed aetiological agents other than the 3 atypical pathogens, the most frequently diagnosed pathogens being Streptococcus pneumoniae (n = 18), Haemophilus influenzae (n = 17), Gram-negative rods (n = 13), Moraxella catarrhalis (n = 6) and Staphylococcus aureus (n = 6). More than 1 pathogen was found in 13 patients. Atypical pathogens were found more often in the young age group (0-18 y), in contrast to bacterial pathogens that were found more often in the older age groups (> or = 65 y). Atypical pathogens were found less often in patients with a clinical presentation of atypical pneumonia. Legionella species other than L. pneumophila were found by PCR in 13 patients (8%), and in 6 patients in combination with another pathogen. An atypical pathogen (M. pneumoniae, C. pneumoniae or L. pneumophila) was found in 17% of the patients hospitalized with a community acquired respiratory infection, predominantly in the young age group. The role of Legionella non-pneumophila species as pathogen in community acquired respiratory infection needs to be determined. The clinical presentation does not predict the type of pathogen found.     

非典型病原菌致成人社区获得性肺炎患者的临床特点分析

目的 研究非典型病原菌感染在成人住院社区获得性肺炎中的重要地位,并对其临床特点进行分析.方法 收集2005年5月至2008年5月来自国内多中心的153例成人社区获得性肺炎住院患者急性期及恢复期双份血清和急性期痰标本,采用间接免疫荧光法检测肺炎衣原体IgG抗体及嗜肺军团菌IgG、IgA及IgM混合抗体滴度,采用被动凝集法检测肺炎支原体IgG、IgA及IgM混合抗体滴度,同时对153份急性期痰标本进行普通细菌培养.用回顾性分析方法了解非典型病原菌在成人社区获得性肺炎住院患者中的地位.结果 153例血清学检测结果中符合非典型病原菌致社区获得性肺炎诊断标准的52例(34.0%),其中47例为单一非典型病原菌感染,其中肺炎衣原体38例,肺炎支原体4例,嗜肺军团菌5例;5例为2种非典型病原菌混合感染,其中肺炎衣原体+肺炎支原体2例,肺炎衣原体+嗜肺军团菌3例;52例中合并细菌感染者11例.结论 非典型病原菌(肺炎衣原体、肺炎支原体及嗜肺军团菌)为成人住院社区获得性肺炎的重要致病菌,以肺炎衣原体为主,同时不能忽视合并细菌感染情况的存在.     

Epidemiology, clinical characteristics and antimicrobial resistance patterns of community-acquired pneumonia in 1702 hospitalized children in Singapore

OBJECTIVE AND BACKGROUND: Childhood community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide. The features of childhood CAP vary between countries. The aim of this study was to delineate the clinical characteristics, complications, spectrum of pathogens and patterns of antimicrobial resistance associated with hospitalized cases of childhood CAP in Singapore. METHODS: A retrospective study was conducted of patients discharged from Singapore's only children's hospital over a 3-year period with a principal diagnosis of CAP. RESULTS: A total of 1702 children, with a median age of 4.2 years (range: 1 month-16.3 years) were enrolled. A pathogen was identifiable in 38.4% of cases, including Mycoplasma pneumoniae in 20.3%, typical respiratory bacteria in 10.3% (64.6%Streptococcus pneumoniae; 21.7% non-typeable Haemophilus influenzae), viruses in 5.5% and mixed bacterial/viral infections in 2%. The majority of M. pneumoniae infections were in school-aged children (>5 years). Severity of infection was greater in CAP caused by typical bacteria, as reflected by length of hospital stay, CRP level, white cell and absolute neutrophil counts. Mortality from typical bacterial infections (8.9%) exceeded that from M. pneumoniae (0.3%) and viral pneumonias (0%) (P < 0.001). Aminopenicillins were often prescribed empirically for suspected S. pneumoniae and H. influenzae infections; however, resistance to these agents was frequently documented among S. pneumoniae (58.5%) and H. influenzae isolates (51%). CONCLUSION: In Singaporean children hospitalized with CAP, M. pneumoniae is the most commonly identified causative organism, followed by common respiratory viruses, S. pneumoniae and H. influenzae. Streptococcus pneumoniae and H. influenzae are associated with greater severity of infection than other organisms, and have high levels of resistance to commonly prescribed antibiotics.     

Etiology of community-acquired pneumonia treated in an ambulatory setting

BACKGROUND: Very few studies have addressed the etiology of community-acquired pneumonia (CAP) treated in an ambulatory setting. METHODS: Patients were recruited from physicians' offices and from Emergency Rooms in Canada. Pneumonia was defined as two or more respiratory symptoms and signs and a new opacity on chest radiograph interpreted by a radiologist as pneumonia. Blood and sputum for culture as well as acute and convalescent serum samples for serology were obtained. Antibodies to Mycoplasma pneumoniae and Chlamydia pneumoniae were determined using enzyme-linked immunosorbent assays. RESULTS: Five hundred and seven patients were enrolled in the study; 419 (82%) had blood cultures done, seven (1.4%) of which were positive for Streptococcus pneumoniae; 241 (47.5%) had a sputum processed for culture, 31% of which were positive for a potential respiratory pathogen. 437 (86.2%) had both acute and convalescent serum samples obtained, 148 (33.8%) of which gave a positive result. Overall an etiological diagnosis was made in 48.4% of the patients. M. pneumoniae accounted for 15% of the cases, C. pneumoniae 12%, S. pneumoniae 5.9% and Haemophilus influenzae 4.9%. CONCLUSIONS: Despite considerable effort an etiological diagnosis of CAP treated on an ambulatory basis was made in only half the patients. The most commonly identified pathogens were M. pneumoniae, C. pneumoniae, S. pneumoniae,     

Etiology of community-acquired pneumonia in immunocompetent adults

In an ideal clinical setting, empiric antimicrobial treatment prescribed in adult community acquired pneumonia (CAP) should be based on national etiological surveillance and in vitro susceptibility assays. Available information about etiology in ambulatory patients and intensive care unit (ICU) patients is scarce, compared to information obtained in hospitalized patients. In studies designed to explore the etiology of pneumonia, no microorganism is detected in 40-50% of patients, a fact that represents limited yields in diagnostic methods. In all settings, Streptococcus pneumoniae is the main respiratory pathogen recovered in adults CAP, being responsible of about 16% of cases among ambulatory patients and about 22% of those admitted to hospital and ICU. About one third of cases are caused by a small group of microorganisms: Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydia pneumoniae, respiratory viruses, Staphylococcus aureus, gramnegative bacillus, Legionella sp; each one is isolated in less than 10% of cases. In general, microorganism distribution varies scarcely in the following attending settings: ambulatory patients, common wards and ICU. An exception is represented by a higher frequency of gram negative bacillus, S. aureus and Legionella sp in ICU, and of C. pneumoniae in the ambulatory setting. In Chile, CAP etiology in hospitalized adult patients is similar to foreign reports; no systematic information has been collected about the etiology in neither ambulatory patients nor in severe CAP.     

Community-acquired pneumonia in southeast Asia: the microbial differences between ambulatory and hospitalized patients

STUDY OBJECTIVES: To determine microbial agents causing community-acquired pneumonia (CAP) in Southeast Asia. DESIGN: A prospective study. SETTING: Three general hospitals in Thailand. PATIENTS: Two hundred forty-five adult patients fulfilling the clinical criteria of CAP from September 1998 to April 2001. INTERVENTIONS: Investigations included sputum Gram stain and culture, blood culture, pleural fluid culture (if presented), urine antigen for Legionella pneumophila and Streptococcus pneumoniae, and serology for Mycoplasma pneumoniae, Chlamydia pneumoniae, and L pneumophila. RESULTS: There were 98 outpatients and 147 hospitalized patients included in the study, and an organism was identified in 74 of 98 outpatients (75.5%) and 105 of 147 of the hospitalized patients (71.4%). C pneumoniae (36.7%), M pneumoniae (29.6%), and S pneumoniae (13.3%) were the most frequent causative pathogens found in outpatients, while S pneumoniae (22.4%) and C pneumoniae (16.3%) were the most common in hospitalized patients. There was a significantly higher incidence of C pneumoniae (36.7% vs 16.3%, respectively; p < 0.001) and M pneumoniae (29.6% vs 6.8%; p < 0.001, respectively) in the outpatients than in the hospitalized patients. The incidence of S pneumoniae, L pneumophila, and mixed infections was not different between the groups. Mixed infections were presented in 13 of 98 outpatients (13.3%) and 9 of 147 hospitalized patients (6.1%), with C pneumoniae being the most frequent coinfecting pathogen. CONCLUSIONS: The data indicate that the core organisms causing CAP in Southeast Asia are not different from those in the Western countries. The guidelines for the treatment of patients with CAP, therefore, should be the same.     

Prospective epidemiologic survey of patients with community-acquired pneumonia requiring hospitalization in Switzerland.

BACKGROUND: Community-acquired pneumonia (CAP) is a common problem and the principal infection requiring hospitalization, but its treatment is complicated by the difficulty in microbiological diagnosis and the increasing incidence of antibiotic resistance among respiratory pathogens. The purpose of this paper is to present the main epidemiologic features of patients with CAP requiring hospitalization in our country. METHODS: We enrolled three hundred and eighteen adult patients with CAP requiring hospitalization in seven large medical centers in Switzerland during two winter periods. The patients' mean age was 70.4 years. This study describes the epidemiology of these patients. Clinical, radiologic and microbiological evaluations were performed at study entry during treatment, and at 4 weeks post-therapy. For microbiological diagnostic purposes, sputum culture, throat swab culture, PCR, blood cultures, Legionella urinary antigen and serologic evaluations were also performed. RESULTS: Despite the higher mean age, the overall mortality rate was 8%, lower than in other comparable studies. The most common underlying diseases present at study entry were cardiac failure (23%), chronic obstructive pulmonary disease (20%), renal failure (15%), and diabetes (12%); 40% of the patients were smokers. Although dyspnea, cough and positive pulmonary auscultation findings were present in about 90% of patients, fever >38 degrees C was present in only 64%. The most frequently isolated respiratory pathogens were Streptococcus pneumoniae (12.6%), Haemophilus influenzae (6%), Staphylococcus aureus (1.6%), and Moraxella catarrhalis (1.6%). Atypical pathogens were frequently found, with the following distribution: Mycoplasma pneumoniae, 7.5%; Chlamydia pneumoniae, 5.3%; and Legionella pneumophila, 4.4%. The mean duration between onset of symptoms and hospital admission was 4.8 days, and the mean treatment duration was 12.1 days. Two weeks after the start of therapy, although clinical symptoms were absent, radiologic infiltrates were still present in 24% of patients. CONCLUSIONS: The microbiological diagnosis in CAP can be established in only about 50% of cases with the combination of several diagnostic tools. Epidemiologic surveys of CAP should be performed on a regular basis, regionally, as a way to improve the management of these infections.     

Epidemiology of micro-organisms responsible for community-acquired pneumonia]

Pneumonias occupy a prominent situation among lower respiratory tract infections where they are remarkable for their potential mortality and for our relative knowledge of the responsible micro-organisms. Analysis and synthesis of each series published must answer several questions, such as: what are the lung diseases considered? which investigations have been performed? which criteria of imputability have been used? in which patients has the study been carried out? in which place, which period and which structure? In spite of methodological lacunae and of the inhomogeneous answers to the questions asked, there is some concordance between the series found in the literature. Thus, more than 90% of community-acquired pneumonias with microbiological identification are caused by Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia psittaci (or pneumoniae), or Influenza A virus.